linux-stable.git/drivers/block/zloop.c, branch v7.3-rc2

loop, zloop: fix dma_alignment for large or unreported limits

2026-09-01T14:42:54+00:00

A file system sets STATX_DIOALIGN with zeroed alignments when the file
can't be used for direct I/O. The zero underflowed to UINT_MAX and
triggered a queue limits validation warning. Fall back to the block
device's limits when dio_mem_align isn't reported.

A file system with a block size larger than PAGE_SIZE may also report a
memory alignment that can't be expressed as a queue limit. File systems
fall back to buffered I/O for requests that don't meet their alignment,
so cap the reported limit to the largest possible value.

Fixes: 6c8dec275ccc ("loop: set dma_alignment from the backing file for direct I/O")
Fixes: c5059c1af2bd ("zloop: set dma_alignment from the backing files for direct I/O")
Reported-by: syzbot+ac00e7bf7ac8c91af921@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ac00e7bf7ac8c91af921
Signed-off-by: Keith Busch 
Reviewed-by: Christoph Hellwig 
Link: https://patch.msgid.link/20260810164218.3721636-1-kbusch@meta.com
Signed-off-by: Jens Axboe

block: rename bi_bvec_done

2026-08-06T12:47:33+00:00

struct bvec_iter::bi_bvec_done is used an offset in the current bvec,
let's rename it accordingly for better clarity. I also plan to use it
for non-bvec based iteration in the future like dma-buf, so drop the
"bvec" part.

Suggested-by: Christoph Hellwig 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Pavel Begunkov 
Link: https://patch.msgid.link/4e4c21858705a200bd8848ffe4080522e3eb5c1c.1786018753.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

zloop: truncate finished zones to zone capacity

2026-08-04T12:55:08+00:00

The size of a sequential zone backing file records the amount of data
written and is used to restore the zone state. A backing file whose size
is equal to the zone capacity is restored as a full zone, while a file
larger than the zone capacity is rejected as invalid.

However, zloop_finish_zone() currently truncates the backing file to the
zone size. For devices with a reduced zone capacity, finishing a zone
therefore creates a backing file larger than the zone capacity. After the
device is removed and later re-added, that zone file is rejected instead
of being restored as a full zone.

Truncate finished sequential zones to the zone capacity, matching the
persistent representation accepted by zloop_update_seq_zone() for a full
zone.

Suggested-by: Damien Le Moal 
Fixes: eb0570c7df23 ("block: new zoned loop block device driver")
Cc: stable@vger.kernel.org
Signed-off-by: Xu Rao 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Link: https://patch.msgid.link/B39E5FD81D1A07F4+20260804023403.939767-1-raoxu@uniontech.com
Signed-off-by: Jens Axboe

zloop: set dma_alignment from the backing files for direct I/O

2026-07-30T21:54:07+00:00

Direct I/O request's use pages handed to the backing files unchanged, so
the backing's DMA alignment requirement applies. Track dio_mem_align and
advertise it as the device's dma_alignment so we communicate proper
limits and misaligned I/O is rejected here instead of reaching the
backend.

Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Keith Busch 
Link: https://patch.msgid.link/20260720201057.1862857-5-kbusch@meta.com
Signed-off-by: Jens Axboe

zloop: remove irq-safe locking

2026-04-15T19:58:37+00:00

All of zloop runs in user context, so drop the irq-safe locking.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Link: https://patch.msgid.link/20260414081811.549755-7-hch@lst.de
Signed-off-by: Jens Axboe

zloop: factor out zloop_mark_{full,empty} helpers

2026-04-15T19:58:36+00:00

Move a few chunks of duplicated code into helpers.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Link: https://patch.msgid.link/20260414081811.549755-6-hch@lst.de
Signed-off-by: Jens Axboe

zloop: set RQF_QUIET when completing requests on deleted devices

2026-04-15T19:58:36+00:00

Reduce the dmesg spam for tests that involve device deletion.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Link: https://patch.msgid.link/20260414081811.549755-5-hch@lst.de
Signed-off-by: Jens Axboe

zloop: improve the unaligned write pointer warning

2026-04-15T19:58:36+00:00

Use the IS_ALIGNED helper and avoid extra conversions, and tell the
user what the unaligned size is.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Link: https://patch.msgid.link/20260414081811.549755-4-hch@lst.de
Signed-off-by: Jens Axboe

zloop: use vfs_truncate

2026-04-15T19:58:36+00:00

While vfs_truncate does various extra checks that we don't really need,
it is always better to use a VFS helper rather than open coding the
logic.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Link: https://patch.msgid.link/20260414081811.549755-3-hch@lst.de
Signed-off-by: Jens Axboe

zloop: fix write pointer calculation in zloop_forget_cache

2026-04-15T19:58:36+00:00

The write pointer is absolute and in sector units, so we need to
convert it to a relative byte address first.

Fixes: c505448748f7 ("zloop: forget write cache on force removal")
Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Link: https://patch.msgid.link/20260414081811.549755-2-hch@lst.de
Signed-off-by: Jens Axboe